The use of combustible (natural, town, butane) gas flow, control or cut-off valves both in mains and in branches thereof for supplying certain appliances (kitchen, heaters, etc.) consuming the same is known and commonly applied.
In any event, the operating means must primarily meet certain safety requirements, particularly making the mobility of flow control members compatible with the valve being altogether sealed in order to prevent potential gas leaks resulting in deflagration or explosion of gas building up therein.
The purpose of the invention constituting the object of this Patent is to enhance the sealing of known valves for controlling the flow in combustible gas lines, ensuring that they are compatible with the required mobility of the control members.
The valve is of the so-called spherical kind, with a straight or right-angle (90xc2x0) fluid flow and with a full to no flow control by means of a quarter-turn of the turning control.
Its structure comprises the following elements:
A box having a small central cylindrical recess in its bottom inner face for snugly housing a similarly shaped projection existing on the bottom of the valve body, and provided on its neck or top portion with two identical and diametrically opposed notches in the direction of the longitudinal axis, designed to snugly house two diametric projections from the washer limiting the turn of the control to a quarter turn, in order to lock the same.
A straight or right-angle flow spherical valve body provided on its driving shaft with two O-ring seals and centrally at the bottom end of its axis of longitudinal symmetry, with a cylindrical projection which is snugly housed in the respective recess on the box bottom and serves as a mounting guide and a socket for a rotary connection.
An intermediate cylindrical tube-shaped adjusting part between the shaft driving the valve body and the box neck, provided with two peripheral throats on the side surface, each one for housing an O-ring seal.
A washer limiting the turn of the control to a quarter turn, provided with two diametrically opposed radial projections housed within the notches in the valve neck, to lock the washer.
A top control, conventionally connected to the valve body shaft, with two diametrically opposed dissymmetrical projections, one being wider and shorter for ease of turning drive pressure and the other one being narrower and longer for a better grip.
The means designed to ensure sealing of the valve are the following:
Two O-ring seals each inserted in a peripheral throat on the valve body shaft.
Two O-ring seals each inserted in a peripheral throat on the side surface of the intermediate adjusting part.
Two annular elastic seals arranged between the flow passages in the valve box and the surface of the spherical body.
An inwardly directed top rim on the neck of the box is also, provided after fitting the washer for limiting rotation in its housing. The mechanical step to draw in the edge of the neck can be made because the depth of its notches is greater than the thickness of the washer, which is thus retained in its seat by the rim provided, without being able to come loose even if the internal valve pressure rises, thereby not only ensuring that the valve is sealed but moreover that it is altogether inviolable and even tamper-resistant, and therefore that the valve is safe against deflagration or explosion.